Legends of Tomorrow finally premieres tonight, and although it looks like a fun show anyone could jump into, it's more fun to know the backstories of all the characters. All of the main heroes/villains, with the exception of Rip Hunter, have enjoyed elaborate introductions on Arrow, The Flash, or both, so if you missed any of these thinly-veiled backdoor pilots, here's everything you need to know about the Legends:

Sara Lance/White Canary

In Arrow, Sara Lance started off as Oliver Queen's dead ex-girlfriend, came back to become a bad-ass vigilante and a breakout character, was tragically killed in the third season, inspiring her sister, Laurel, to become Black Canary. She was then resurrected in the Lazarus Pit in season four, which, as we all know, has some heavy psychological consequences. In the comics, White Canary is a distinct character from Black Canary, but in the DCTV universe, White Canary is the mantle taken on by a former Black Canary after undergoing some grueling transformation.

Martin Stein/Firestorm

Martin Stein was one of the metahumans created by the accident at S.T.A.R. Labs that also created the Flash. He was a nuclear physicist focused on transmutation and developed the ability to merge with Ronnie Raymond to become Firestorm. When a black hole singularity threatened to engulf Central City, Ronnie sacrificed himself to close it, and Barry was only able to save Stein. But then, Stein began to experience health problems that indicated his Firestorm matrix was unstable without a partner, which led to his partnership with a new character, Jefferson "Jax" Jackson.

Jax Jackson/Firestorm

Jax is a former high school football star who was injured in the particle accelerator accident, prematurely ending his athletic career. He was at first reluctant to merge with Stein, but agreed after the only other candidate used his powers for evil.

Ray Palmer/Atom

Ray Palmer was a CEO and inventor who once had a relationship with Oliver Queen's Girl Friday, Felicity Smoak. He designed an exosuit that allowed him to shrink down to subatomic level while maintaining his natural strength level. When he first tried out this feature of his suit, he was thought dead by Team Arrow, until he finally managed to contact Felicity and was subsequently captured by Damien Darkh for his technology. Team Arrow managed to save him in the end, and he continued to aid them with his inventions.

Leonard Snart/Captain Cold

Leonard Snart is a supervillain on The Flash. After an abusive childhood, he teamed up with Mick Rory/Heat Wave to commit high-stakes robberies using a stolen cryonic gun that can freeze objects (and people) with a single shot. He is generally an adversary for Barry, but has somewhat begun a redemption arc on The Flash. Most recently, he appeared on The Flash's midseason finale when the Weather Wizard broke him out of prison, but instead of trying to kill Barry, he warns him and gives him intel.

Mick Rory/Heat Wave

In addition to being Leonard Snart's other half, Rory is an arsonist, equipped with a heat gun that can burn almost anything. He hasn't been as well-developed as Snart, mostly acting as his sidekick, but hopefully that will change in Legends of Tomorrow.

Kendra Saunders/Hawkgirl

Kendra Saunders was introduced on The Flash as an innocuous love interest of Cisco, but turned out to be Hawkgirl, a young woman who is just realizing that she has been reincarnated many times over the centuries. When she feels threatened, her warrior persona comes out, along with wings that grow out of her back. She and Hawkman assisted Barry and Oliver in their fight against Vandal Savage and were killed, but Barry went back in time and saved them.

Carter Hall/Hawkman

Carter Hall is Kendra's "soulmate" who is fated to be reincarnated with her for eternity. He is the reincarnation of the Egyptian prince Khufu, and reveals to Kendra that Vandal Savage has killed them in every lifetime, growing stronger with each kill.

Rip Hunter

A new addition to the Flarrow universe, Rip Hunter is a time traveler (amusingly played by Doctor Who's Arthur Darvill), who is responsible for the fate of history itself, driving him to bring the Legends together.

Vandal Savage

Vandal Savage is a 4,000-year-old supervillain, an Egyptian priest who gained immortality by consuming the souls of the prince and princess, Khufu and Chay-Ara (Hawkman and Hawkgirl, respectively). He goes on to manipulate leaders throughout history in order to take over the world, even serving as Julius Caesar and Genghis Khan's most trusted advisor. He was killed by Barry and Oliver after Barry went back in time to reverse Hawkman and Hawkgirl's deaths, but Malcolm Merlyn collected his ashes saying that he "owed him one," implying that he will bring Vandal back to life before the events of Legends of Tomorrow.